13870781 has 4 divisors (see below), whose sum is σ = 14165952. Its totient is φ = 13575612.

The previous prime is 13870763. The next prime is 13870799. The reversal of 13870781 is 18707831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18707831 = 397 ⋅47123.

It is an interprime number because it is at equal distance from previous prime (13870763) and next prime (13870799).

It is a cyclic number.

It is not a de Polignac number, because 13870781 - 2¹⁴ = 13854397 is a prime.

It is a super-2 number, since 2×13870781² = 384797131099922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13870721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147515 + ... + 147608.

It is an arithmetic number, because the mean of its divisors is an integer number (3541488).

Almost surely, 2^13870781 is an apocalyptic number.

It is an amenable number.

13870781 is a deficient number, since it is larger than the sum of its proper divisors (295171).

13870781 is an equidigital number, since it uses as much as digits as its factorization.

13870781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295170.

The product of its (nonzero) digits is 9408, while the sum is 35.

The square root of 13870781 is about 3724.3497419013. The cubic root of 13870781 is about 240.2704185727.

The spelling of 13870781 in words is "thirteen million, eight hundred seventy thousand, seven hundred eighty-one".